Endocrinology Practice Questions

Correct Answer: B

Rationale: Excess prolactin causes gynaecomastia due to its stimulatory effect on breast tissue growth in males. Prolactin inhibits the release of testosterone, leading to an imbalance in sex hormones and breast tissue development. Acromegaly is caused by excess growth hormone, not prolactin. Early menopause is unrelated to prolactin levels. Anaemia is typically not associated with prolactin excess. Thus, gynaecomastia is the most appropriate outcome of excess prolactin.

Correct Answer: B

Rationale: Correct Answer: B (Rheumatic carditis) Rationale: 1. Rheumatic carditis is a heart condition, which may lead to a decreased cardiac output and subsequently a lower pulse rate during sleep. 2. Anxiety neurosis can lead to increased sympathetic activity, causing an elevated pulse rate during sleep. 3. Pulmonary tuberculosis can cause systemic inflammation and increased metabolic demand, resulting in an elevated pulse rate during sleep. 4. Atropine, a parasympatholytic drug, inhibits the action of the parasympathetic nervous system, leading to an increased pulse rate.

Correct Answer: C

Rationale: The correct answer is C: Stress. Stress triggers the release of growth hormone through the activation of the hypothalamic-pituitary-adrenal axis. When the body is under stress, the hypothalamus signals the pituitary gland to release growth hormone. This hormone then stimulates growth and cell reproduction. Glucocorticoids (A) and somatostatin (B) actually inhibit the release of growth hormone. Obesity (D) can lead to decreased growth hormone release due to disrupted hormonal regulation. In summary, stress is the correct answer as it directly stimulates the release of growth hormone, while the other choices inhibit or have a negative impact on growth hormone release.

Correct Answer: B

Rationale: Excess prolactin causes gynaecomastia due to its stimulatory effect on breast tissue growth in males. Prolactin inhibits the release of testosterone, leading to an imbalance in sex hormones and breast tissue development. Acromegaly is caused by excess growth hormone, not prolactin. Early menopause is unrelated to prolactin levels. Anaemia is typically not associated with prolactin excess. Thus, gynaecomastia is the most appropriate outcome of excess prolactin.

Correct Answer: D

Rationale: The correct answer is D: second messengers. Protein hormones typically bind to cell surface receptors, activating second messenger systems to relay the signal inside the cell. This mechanism allows for rapid and amplified cellular responses. Choices A and B (cytoplasmic and nuclear receptors) are more commonly associated with steroid hormones, not protein hormones. Choice C (cyclic ribosomal adenosine phosphate) is not a known mechanism of hormone action. Thus, the correct answer is D, as second messengers are the primary mediators of protein hormone actions.